Certain athletic shoes for field sports such as baseball have a number of blade-like cleats (or "spikes") for the purpose of increasing traction. Such cleats or spikes dig into the ground to prevent slipping during starting, stopping and cutting maneuvers.
However, in addition to providing desirable traction for starting, stopping and cutting, such cleats typically provide undesirable resistance to pivoting. This can be a disadvantage in at least two ways.
First, the resistance of many prior art cleating arrangements to turning movements can create stresses within the leg when unwanted torque or force is applied to the athlete, particularly to the athlete's leg. Injuries, particularly knee and ankle injuries, can result if a twisting movement is forcibly applied to a leg at a time when the cleats are firmly planted in the turf and release is difficult or impossible.
Second, when pivoting is inhibited, maneuverability of the athlete is limited, thus making performance less than it could be. Enhancing the ability of a player to pivot while still maintaining good traction and foot stability can greatly increase effectiveness on the field.
When pivoting is inhibited, the maneuverability of the athlete is limited and performance is less than it could be. Enhancing the ability of a player to pivot while yet maintaining or improving stability and traction in foot motions not involving pivoting can greatly increase effectiveness on the field.
Pivotability is of great importance In baseball in a number of common motions. For example, pivoting is important in batting to avoid certain unnatural motions which occur because of poor pivotability, in pitching on both the lead foot and the drive foot in fielding such as in turning to make a throw.
Attention has been given to improving pivotability in cleated athletic shoes. One example of a blade-like cleat is shown in U.S. Pat. No. 4,347,674, which shows three arcuate spikes widely spaced along a circular path to facilitate pivoting. Both the configuration of such cleats, with their flat ends which are vertical (that is, perpendicular to the main sole surface), and the widely spaced arrangement of such cleats, spaced apart in fact by dimensions well in excess of spike width, are such that any resulting improvement in pivotability will not be very substantial. The configuration and spacing of such cleats is not conducive to excellent pivotability.
Such vertical ends are disadvantageous because they present a long edge for cutting the full depth of the penetrated ground during pivoting motions. This edge arrangement results in fairly high resistance to pivoting. And, the wide spacing means that fresh ground or turf is being cut for most or all of many pivoting motions.
In addition, such blade cleat has a distal edge which is generally parallel to the main sole surface along all or nearly all the width of the cleat. Such relatively long sole-parallel distal edge presents a surface which is more resistive to penetration of the ground. With such a cleat, it becomes more difficult to penetrate ground with harder surfaces, especially for players of lighter body weight.
In addition to the structural features described above, there are other structural features of prior blade-like cleats which are disadvantageous in certain situations. Some background discussion is necessary for proper understanding.
First, attention is drawn to the recent developments in athletic shoe cleating made by Michael L. Tanel, the inventor herein, involving annular cleating which provides a combination of greatly improved pivotability and excellent traction. These developments tend to reduce the chance of athletic injuries and significantly improve maneuverability on the field. Examples of such cleating are disclosed in U.S. Pat. Nos. 4,577,422, 4,653,206, 4,660,304, 4,669,204, 4,723,365 and 4,748,752.
The improvement in pivotability made possible with shoes in accordance with the principles of such patents is dramatic, and such shoes give the athletes wearing them a natural feeling of freedom together with good feeling of traction for stopping, starting and cutting.
These Tanel inventions have been commercially embodied in shoes having cleats which are integrally formed with soles and have tapered sides, rather than in spike-like cleats. One significant feature of such annular cleating arrangements is the substantially continuous nature of an annular cleat. Such a degree of continuity becomes somewhat problematic when blade-like cleating, using metal or other rigid material, is contemplated.
Blade-like cleats like those in the aforementioned U.S. Pat. No. 4,347,674 have a base plate which is attached to the blade portion of the cleat at generally right angles and which is used for securing the cleat to the sole of an athletic shoe. Attachment may be by threaded fasteners or by injection molding a bonding material over the base plate. Characteristically, such base plates of blade-like cleats of the prior art have a width which is significantly greater than the width of the blade to which they are attached. Such greater width is deemed essential to firmness of attachment to the sole, particularly when attachment is by securement by virtue of injection molding over the base plate.
However, to obtain the benefits of pivotability of substantially continuous annular cleating, and to do so without loss of sole flexibility, close spacing of discrete blade-like cleats is essential. Indeed, abutting or nearly abutting cleats is highly desirable. Such cleat "density" provides improved traction with little or no impairment of pivotability.
Unfortunately, the undue width of earlier cleat base plates rules out such close or nearly abutting arrangement of cleats. As a consequence, with such blade-like cleats of the prior art it has not been reasonably possible to construct an athletic shoe which maximizes cleat density for maximum traction. And, to merely reduce the width of the cleat bases would tend to substantially weaken the engagement of the cleat with the sole.
Another very practical consideration for athletic shoes which would have an annular arrangement of closely spaced cleats relates to the fact that athletic shoes obviously must come in a wide variety of sizes. Because of such wide variations in size, a wide variety of cleat sizes and widths could be thought to be necessary. This would complicate manufacturing and greatly increase manufacturing costs. The presence of multiple cleat sizes at the assembly station would tend to cause manufacturing errors such as selecting a cleat of improper size for a particular shoe being assembled. A universal cleat would be highly desirable.
Referring again to ease of ground penetration, consideration must also be given to the total area of the cleat edges which initially engage the turf. The greater the total area bearing on the turf, the more difficult it may be for a cleat to penetrate the ground; the smaller the total area bearing on the ground, the easier it may be for a cleat to penetrate. Reducing the blade width reduces the area of the distal ends. However, structural weakness may result from reduced cleat width and cleat deformation or breakage will likely result.
To the extent that reducing cleat width adds sharpness, there would be an increased risk of "spiking" injury. And, regardless of width, sharp corners between , the vertical sides of certain prior art cleats and their long horizontal distal edges can pose an undue- risk of injury.
Still another problem with certain cleated shoes of the prior art is that the pressure of the individual cleats can be felt by the foot of the athlete. Because of this, shoe comfort is reduced. The aforementioned annular cleats tend to overcome this problem, but for shoes with discrete blade-like cleats, this problem can be significant, particularly on hard ground.
Yet another concern with certain blade-cleated shoes of the prior art is that their low number of cleats on the forefoot provides insufficient traction during certain movements. Traction through a wide range of athletic moves is highly desirable. And, many blade-cleated shoes of the prior art have cleating arrangements which do not have sufficient spread to provide good support. In some cases, insufficient ankle stability is a result.
A few general comments are in order before turning to a description of this invention. In particular, a brief description of the foot and its pivoting and planted positions will be helpful. This can serve as an aid in understanding certain embodiments of this invention.
The sole of the foot includes four portions. These are, in order from back to front: the heel portion; the arch portion; the ball-of-the-foot portion; and the toe portion. The heel portion and the ball-of-the-foot portion are those portions which share most if not all of the player's weight when the player is in a normal standing position with feet generally flat on the ground. In such position, the arch portion and toe portion bear little if any weight.
When a player is "on his toes" in a "ready" position, virtually all of the player's weight is normally shared by the toe portion and the ball-of-the-foot portion. The same is usually true when a player is "digging" in a running action. Indeed, when a player is in the ready position, the juncture of the phalanges (toe bones) and the metatarsals is the center of weight bearing. In other words, the center of weight bearing in the forward portions of the foot actually moves forward when a player shifts to the ready position.
The sole of an athletic shoe has portions immediately below these four portions of the foot which may be designated, and herein are designated, by the same terms.